Device and method for raising sunken objects

ABSTRACT

A device and method for raising sunken objects such as crates, small boats, vessels and ships including a platform equipped with winches to lower down a basket net and a frame supporting a cryogenic apparatus to the vicinity of the object. The cryogenic apparatus is adapted to pump surrounding water through a freezing unit to reduce its temperature to below freezing and then form a stream of overcooled water directed over the sunken object to form a layer of ice about it. The basket net contains provisions to allow its closure under the object once it is lifted off the sea floor. Once enough ice is formed, the object is lifted to the surface. On average, the capacity of the cryogenic apparatus is such that a 1 ton object can be lifted in about 3 hours. Remote monitoring and control means are provided for the operator to observe and direct the operation of the device. The device is especially advantageous in dealing with explosive objects such as old and unwanted sea mines, torpedoes and alike.

BACKGROUND OF THE INVENTION

The present invention relates generally to a device and a method forraising sunken objects including small ships and vessels. Moreparticularly, the present invention describes the use of overcooledwater to form a layer of ice about the sunken object to temporarilyincrease its buoyancy.

The problem of recovering sunken objects has been around for hundreds ofyears. In a typical situation, the sunken object such as a small vesselis pulled up by hoisting cables wrapped about the object. This methodhas a major disadvantage in that the cables or ropes have to be wrappedfirst about the object and then the object can be pulled to the surface.At depths greater than divable depths, this procedure can not be easilyaccomplished since divers are generally needed to position and securethe cables around the object.

Attempts have been made to fill the hull of the vessel with particulatelighter than water and therefore increase the buoyancy of the object soit can be lifted easier. This method is also difficult to achieve as thehull is not always intact and may have openings at different locationsmaking it impossible to contain the filling particulate inside.

Another method known in the prior art is to submerge a hollow chambernext to the object and then attach it to the object. Air is then pumpedinto the chamber to allow for its lifting together with the object. Thismethod is rather complex and requires a large hollow chamber to beavailable so a designating recovery ship is usually needed for thisoperation.

The use of ice is also known in the art of recovery of sunken objects.The advantage is that ice weighs less than water and by attaching alarge amount of ice to the sunken object, its buoyancy can be increased.Ice may be formed onsite and therefore easily available. Once on thesurface, the ice is simply discarded back into the water.

Several patents of the prior art describe various methods of using iceto recover sunken objects. U.S. Pat. No. 4,690,087 as well as RussianPatents SU 1,785,948; RU 2,009,954; and RU 2,192,985 incorporated hereinin their entirety by reference, all describe devices supplying liquidnitrogen or another cryogenic liquid through a network of channelsplaced about the sunken object to attach that network to the object andform ice about thereof. These methods and devices have limited efficacysince the ice can be formed only up to certain depth about such pipesdue to the fact that further increase in depth is limited by theprevious layer of ice already formed around each pipe. Therefore, thedevices become more complex as more and more pipes are needed bothinside and outside the vessel hull. In addition, assembling andsubsequent dismantling of the pipe network around the vessel iscomplicated and requires significant efforts.

The need therefore exists for a simple cryogenic device and method forraising sunken objects without the need for complicated pipe network tobe constructed around the object and providing an ability to attach iceof substantial thickness to the sunken object so that it can be easilylifted to the surface.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to overcome theseand other drawbacks of the prior art by providing a novel device andmethod for raising sunken objects in which the overcooled water issupplied from a cryogenic apparatus to form ice about the sunken object.

It is another object of the present invention to provide a device andmethod for raising sunken objects by increasing the buoyancy of theobject as a result of attaching a layer of ice about the exterior andinterior of the object.

It is a further object of the present invention to provide a device forraising sunken objects which is simple to operate and small in size soas it can be transported to the site by a regular ship.

It is a further yet objective of the present invention to provide adevice and method to cover the sunken object with ice of desirablethickness and at desirable locations.

It is yet a further object of the present invention to provide a devicefor raising the sunken objects equipped with a rope and cable basketadapted to envelope the object without tangling on itself.

The device and method of the invention are based on providing a highflow velocity cryogenic apparatus capable of forming an underwaterstream of overcooled water and directing it over the desired locationsof the sunken objects. The water is cooled to the temperature belowfreezing but is still flowable while inside the device because of itshigh velocity. Once the stream of such water reaches the sunken object,freezing of the water causes ice forming on the surface thereof.

The device of the invention is therefore rather small and portable andso it can be easily transported to a site where the sunken object islocated by a regular ship or boat. Its operation is also not complicatedsince no great precision is needed to direct the stream towards thesunken object. Another important advantage is that the thickness of theice layer is determined by the duration of supplying the stream ofovercooled water to a particular location and can theoretically beunlimited and not dependent on the piping network as in the prior artdevices. This allows easy balancing of the patches of ice all the wayaround the object if it is large so a uniform lifting force can becreated and the object can be lifted straight up.

A variety of objects can be raised from the sea floor including smallobjects like crates, barrels, antique canons and such as well as smalland medium size entire boats, ships and vessels.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the presentinvention and the various advantages thereof can be realized byreference to the following detailed description in which reference ismade to the accompanying drawings in which:

FIG. 1 is side view of a raising platform with the cables and basketnet;

FIG. 2 is a side view of the raising platform of the device, a cryogenicovercooled water supply apparatus and a cable and basket net wrappedabout the sunken object at the beginning of the process of raising theobject;

FIG. 3 is a side view of all the above elements of the device after thecable is pulled, the sunken object and the basket net enveloping thereofare both covered with a layer of ice and ready for lifting to thesurface; and

FIG. 4 is a side view in cross-section of control unit of the cable andbasket net.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

A detailed description of the present invention follows with referenceto accompanying drawings in which like elements are indicated by likereference letters and numerals.

At the heart of the present invention is the raising platform 1 shown onFIG. 1. It comprises a four-sided frame 2, which can in turn be attachedto or suspended from a salvage ship as well as be hollow so as to floaton water itself and be capable of supporting the sunken object at theend of the salvage procedure.

On the top of the raising platform there are attached two pairs ofwinches 4, 5, 6, and 7, each having a corresponding cable 8, 9, 10, and11 equipped with an anchor or a weight 12 at the end thereof. The sideof the raising platform 1 that is free of the above-mentioned winches 4,5, 6, or 7 contains a raising winch 13 with a raising cable 14. Arectangular or square basket shaped inverted net 15 with an open bottomis adapted to be moved up and down the cables 8, 9, 10, and 11 by havingrings 16 on the corners of its inverted bottom sliding along cables 8through 11. The basket net 15 may be made out of ropes, cables and alikeas long as it is made strong enough to support the sunken object. Thelower portion of the basket net 15 is equipped with three breakawayrings 17 at its three corners sliding along the cables 8, 9, and 10. Thefourth corner has a control unit 18 attaching thereof to the cable 11.Air-filled chambers may be optionally attached to the basket net 15 (notshown on the drawing) so as to better control its shape during thevarious maneuvers of the salvaging operation as well as to furtherincrease the buoyancy of the sunken object. The lower part of the basketnet 15 also contains a plurality of rings 19.

While rings 16 and 19 are made from a durable material such as metal,rings 17 are made from a material which easily breaks under load such asplastic because of the reasons explained in more detail below.

The control unit 18 comprises a cylindrical housing 20 containing abraking unit 21 (see FIG. 4). At the bottom of the control unit 18 thereis provided a connector tube 22 two openings 23. Importantly, the sizeof the openings 23 is smaller than the breakaway rings 17. The breakingunit 21 contains two electromagnets 25, connected through the springs 26with the braking pads 27, adapted to surround but normally not touch thecable 11. In an alternate configuration, the pads 27 are normally lockedabout the cable 11 by the action of the springs 26. Electromagnets inthat case are adapted to pull the pads aside when activated to releasethe cable 11.

Cable 28 is pulled through the rings 24 on top of the control unit 18.Cable 29 is pulled through the rings 19 located on the bottom of thebasket net 15 and the openings 23 inside the housing 20. The ends of thecable 29 are pulled through the connector tube 22 outside the housing 20and are connected together forming therefore the loop 30. The loop 30 inturn is connected to the cable 14 and the raising winch 13. Importantly,the cable 29 is made to be heavier (from metal for example) than thecable 28 so as not to tangle with it during the manipulations of thedevice. This provides for easy lowering of the entire basket net 15during the first stages of the raising operation.

FIGS. 2 and 3 further illustrate the additional frame 31 suspended fromthe raising platform 1 on the cables 8, 9, 10, and 11. It can be raisedand lowered with an additional winch and cable (not shown on thedrawings). The corners of the frame 31 are equipped with hollowcylinders 32 having stops (not shown) adapted to bring the frame 31 to apredetermined depth along the cables 8 through 11. Optionally, the frame31 also contains remotely controlled visual identification means such aslights and TV cameras to provide information back to the control roomabout the situation under water. Alternately, radar means, ultrasoundmeans, or any other commonly used visualization means may be deployed toprovide the same information to the operators of the device of thepresent invention.

Horizontal rail 33 is mounted inside the frame 31 and supports thecryogenic apparatus 34 mounted thereon with the means of moving andtilting thereof forward and back on the rail 33. The cryogenic apparatus34 in turn comprises a water pump pumping water through a labyrinth of afreezing chamber containing liquid nitrogen or another freezing agent.Importantly, the cryogenic apparatus 34 forms a high velocity stream ofovercooled water at a temperature below normal freezing temperature ofwater so as it reaches the sunken object it slows down and freezes allaround thereof. Remotely controlled technical means are envisionedallowing moving the cryogenic apparatus 34 back and forth along the rail33 as well as tilting it from side to side inside the frame 31. One ormore electrical motors may be used for this purpose for activating asystem of pulleys, gears, levers, mechanical joints, or another commonlyknown mechanisms. The operator from the salvage ship remotely controlsthe movements of the apparatus 34.

In operation, the process of raising the sunken object 3 is started bythe operator of the device turning on the winches 4, 5, 6, and 7 torelease the cables 8 through 11 until the anchors 12 reach the sea floor(see FIG. 2). The rings 16 and 17 as well as the control unit 18 arethen all freely lowered down along the cables 8 through 11 so as tolower the basket net 15 over and about the sunken object 3. The operatorthen brings down the frame 31 on the same cables 8 through 11 and stopsit so that the cryogenic apparatus 34 is located in the near vicinity ofthe object 3 as indicated by the visual control means located on theframe 31.

The operator then activates the cryogenic apparatus 34 to direct theovercooled water stream towards the object 3 and the basket net 15surrounding it to form a controlled layer of ice thereon. The operatorcan control the direction of the water stream by remotely moving thenozzle of the cryogenic apparatus 34 back and fourth and from side toside so as to deliberately form desired thickness of ice at variouspoints along the object 3. As the ice layer forms around the object 3,the top portion of the basket net is encased within the layer of ice andtherefore is attached to the object 3. That process is continuing untilthe amount of ice is enough to lift the object 3 and the basket net 15off the sea floor.

As the object 3 starts to slowly move upwards, the operator activatesthe breaking unit 21 of the control unit 18. Energizing andde-energizing electromagnets 25 counteracts the action of the springs 26allowing the operator to cause the braking pads 27 to either firmly grabor release the cable 11. That action in turn allows the operator tocontrol lifting the position of object 3 close to the bottom and avoiduncontrolled upward movement to the surface. The operator then turns onthe raising winch 13 applying tension on the cable 14 and therefore onthe loop 30. The loop 30 is then pulled away along with the cable 29from the connecting tube 22 and away from the control unit 18. The cable29 then brakes the rings 17 and closes the lower portion of the basketnet 15 about the bottom of the object 3 as the loop 30 is pulled furtherand further away from the control unit 18.

Once the object 3 is surrounded from all sides by the basket net 15, theoperator can again turn on the cryogenic apparatus 34 to increasefurther the thickness of ice around the object so it brings itself tothe surface. Alternatively or in addition to it, the operator can raisethe object as is by activating the winches 4 through 7 of the raisingplatform 1. Of course, the frame 31 is lifted along with the object 3 aswell so as to keep the nozzle of the cryogenic apparatus 34 in operablevicinity of the object 3. The force needed to lift the frame 31 comesfrom either the reactive force associated with the operation of thecryogenic apparatus 34 or from a dedicated winch or alike (not shown).

The speed of raising the object may be conveniently adjusted by turningon and off the action of cryogenic apparatus 34 so as to increase ordecrease the amount of ice around the object 3. Another way to adjustthat speed is to turn on and off the braking unit 21 of the control unit18.

The device of the invention can be used advantageously when liftingexplosive, radioactive, or other dangerous objects from the sea floor.Calculations show that it takes about 3 hours to raise an object havinga weight of about 1 metric ton. This is a rather fast process, whichfurther decreases the risk of an accident associated with salvage andrecovery of such dangerous objects as military mines, torpedoes, andalike. Besides, the presence of a thick layer of ice and remote controlof the entire operation increases the safety even further as well asremoves environmental risks as it reduces the risk of spontaneousexplosion of such an object.

Although the invention herein has been described with respect toparticular embodiments, it is understood that these embodiments aremerely illustrative of the principles and applications of the presentinvention. It is therefore to be understood that numerous modificationsmay be made to the illustrative embodiments and that other arrangementsmay be devised without departing from the spirit and scope of thepresent invention as defined by the appended claims.

1. A device for raising a sunken object comprising: a platformcontaining a cable means and a lifting and lowering means for said cablemeans, a basket net adapted to slide along said cable means and to coversaid sunken object, a frame means adapted to slide along said cablemeans above said basket net, a cryogenic means supported on said framemeans above said basket means and above said sunken object in thevicinity thereof, said cryogenic means further comprising a water pumpadapted to pump said water through a freezing means to bring itstemperature to below its freezing temperature, said pump further adaptedto form a stream of water over said sunken object, and a control systemfor remotely monitoring and controlling the operation of said liftingand lowering means and said cryogenic means.
 2. The device as in claim1, wherein said lifting and lowering means are winches.
 3. The device asin claim 1, wherein said cable means comprising four cables equippedwith anchors at their ends.
 4. The device as in claim 1, wherein saidbasket net having an upper portion and a lower portion of a rectangularshape defining four upper and four lower corners, each upper cornercontaining a first ring sized to slide freely over said cable means. 5.The device as in claim 4, wherein said basket net further comprisingthree breakaway rings at the three lower corners and a control unit atthe fourth lower corner thereof, said control unit adapted to bring allfour lower corners together while under said sunken object to entirelyenclose thereof.
 6. The device as in claim 5, wherein said control unitincluding braking means to control the movement of said control unitalong said cable means.
 7. The device as in claim 6, wherein saidbreaking means further including at least one electromagnet and brakingpads surrounding said cable means.
 8. The device as in claim 1, whereinsaid frame means including a horizontal rail and a remotely controlledtechnical means supporting said cryogenic means on said horizontal rail,said technical means adapted to moving said cryogenic means along saidrail and tilting it from side to side.
 9. The device as in claim 1,wherein said frame means further including remotely controlled visualidentification means.
 10. The device as in claim 9, wherein saidremotely controlled visual identification means including lighting meansand video recording means.
 11. A method for raising a sunken objectcomprising the steps of: a. deploying a basket net over said object, b.providing a cryogenic means and positioning said means above said basketmeans and above said sunken object in the vicinity thereof, c.activating said cryogenic means to pump a stream of overcooled waterover said sunken object, said overcooled water being at a temperaturebelow its freezing temperature after leaving said cryogenic means, d.forming a layer of ice about said object and said basket net to raiseits buoyancy by freezing said overcooled water, and e. bringing up thesunken object once enough ice is formed thereabout.
 12. The method as inclaim 11, wherein said step “e” further comprising a step of enclosingsaid sunken object in said basket net once it is lifted.
 13. The methodas in claim 11, wherein said step “c” further comprising a step orremotely monitoring and controlling the position of said cryogenic meansover said sunken object to form ice at predetermined locations thereofand of predetermined thickness.
 14. The method as in claim 11, whereinsaid step “d” further comprising a step of attaching said basket net tosaid sunken object by forming ice therethrough.
 15. The method as inclaim 11, wherein said step “e” further comprising a step of adjustingthe speed of raising said sunken object by turning on and off saidcryogenic means to selectively increase or decrease the amount of iceabout said object.